Overload-release hook for steam and motor tractors, hoists, and cranes



F. J. S. JONES. OVERLOAD RELEASE-HOOK FOR STEAM AND MOTOR TRACTORS, HOISTS, AND CRANES.

APPLICATION FILED AUG-27.19l9.

, 9 1 Q1. 1 4 11 v f INVENTOR Patented Feb. 15,1921.

UNITED sTA Es PATENT OFFICE.

FRANCIS JOSEPH STAWELL JONES, F POR'I'HCAWL, WALES.

OVERLOAD-RELEASE noon ron STEAM AND MOTOR rnncrons, Hoiscvs, AND ensues.

Patented Feb. 15, 1921.

Application filed August 27, 1919. Serial No. 320,165.

To all to 7mm it may concern Be it known that 1, Franc s Josnrn STAWELL Jones, mechanical engineer, subject of the King of Great Britain, residing at Bryn-y Cae, Porthcawl, W ales, have invented a new and useful Overload-Release Hook for Steam and Motor Tractors, Hoists, and Cranes; and I do hereby declare the fol lowing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to overload release hooks in which the load is transmitted through two fulcrumed levers in such a manner that consequent upon the same exceeding a predetermined value the said levers are caused to turn about their respective pivotsagainst a resisting medium and so effect release of the load being carried.

The objects of the invention are to provide an arrangement which shall be effective in operation cheapin construction and in which adjustments for varying the point of release to suit loads of difierent magnitude may be quickly and easily undertaken.

My invention consists in the particular shape and disposition of two fulcrumed levers hereafter to be more fully described and in the provision of means of resistance to movement of the said levers whereby adjustment may be efiected while under load.

In order that my invention may be fully understood I will now proceed to describe the same by aid of the accompanying drawings in which Figure 1 is a side elevation of the hook with the parts assembled.

Fig. 2 is a side elevation of the two levers disassembled showing clearly the normal relative positions of each.

Fig. 3 is a plan view of Fig. 1 with the means for providing resistance to relative movement of the two levers and the means of adjusting the resistance to relative movement shown in section.

In the drawings the two levers a and b are normally disposed with their adjacent longitudinal edges corresponding preferably in slightly spaced relation to each other in which position they are retained by pivot or fulcrum pins a and b respectively between two parallel side plates 0 c. 7

The lever on is formed at one end with the hook cl which when in operation engages with the draw-bar e, and said hooked lever a has its fulcrum a in close proximity to the drawbar. Fora part of its length the lever a is recessed as at f to permit of the lever 5 being superimposed thereon.

At the point of engagement of the two levers the lever a is formed with a groove Q and the lever b with a projection or spur 7L engaging therewith and near this point the lever Z) is fulcruined as shown at 5. Near its other end the lever b is formed with a semi-circular depression '2' to take a steel ball 2" (see Fig. 3) which latter is acted upon by a 0011 spring j. The pressure is regulated by a set screw Z which adjusts the hook to the load at which it will automatically re lease and can be adjusted while the hook is under load. A. steel cap it is provided to protect the adjusting screw Z.

The casing is composed of two steel plates arranged parallel and in spaced relation w th each other by means of the fulcrum pins a, b and an eye piece 0 which latter is confined between the extremities of the side plates 0, c and held therein by bolts 0 The other end is slotted as at 0 to receive the draw bar e.

In operation the effect of a load is to produce a tendency within the lever a to turn about its fulcrum a. This is transmitted in turn to the lever b by contact with the spur h. Movement of this lever 12 is prevented by the engagement of the balls 71 with the depressions 2' until such time as the load exceeds the predetermined value when the resistance is overcome and the levers turn about their respective pivots and assume approximately vertical positions.

A plurality of the above described levers may be used, if desired to form the hook or the number may be limited to one.

What I claim is 1. In an overload release of the character specified, a casing, a lever fulcrumed to said casing having means at one end for engaging the device to be operated and a recess at the other end, a second lever fnlcrumed to said casing and adapted to rest in superimposed relation upon the recessed portion of the other lever, means on the coacting opposed extremities of the said levers for eifecting engagement therebetween, and adjustable means for engaging the near extremity of the second lever for preventing such lever turning about its fulcrum until a predetermined load has been attained.

2. In an overload release of the character specified, a casing, a lever iulcrumed to said casing having means atone end for engaging the device to be operated, and a recess at the other end, a second lever fulcrumed to said casing adapted to normally rest in superimposed relation upon the recessed J a pressure of the spring on said ball.

3. In an overload release of the character specified, a casing, a lever fulcrumed in said casing having a bent extremity adjacent to the point of fulcrum of said lever, a longitudinal slot in one end of said casing adapted to coact with said bent extremity and provide a means of engaging the device to be drawn, a longitudinal recess at the 'in superimposed relationupon the upper surface of the said recess, a groove in said recessed lever, a spur on the adjacent endof said second lever adapted to normally engage said groove, a spring loaded ball carried by said casing, a depression in the adjacent side of said second lever adapted to be engaged by said ball and screw, means for adjusting the pressure of the spring on said ball.

In testimony whereof I aflix my signature in presence of two witnesses.

FRANCIS J. S. JONES.

Witnesses: V

F H. LITTLE, v, PERCIVAL GARRETT.- 

